Have you hiked in the Sierras? You will bring the same gear as hiking elsewhere in these mountains, as apropos for the season. The traditional trip takes two days to the peak; the stopover is known as Trail Camp. Due to its relatively high altitude, it can get down to freezing at night, even in the summer. Select your equipment accordingly. While most of the Sierras do not require treatment to make water potable, the water quality all along the approach from Whitney Portal are relatively poor during the summer season due to contamination from high traffic, so it behooves you to bring a means to condition all drinking and cooking water.

Train for this hike as you may any other high Sierra hikes. If you can take day hikes in the mountains, by all means do so. The more time spent up high the better your chances at avoiding some of the unpleasant side effects of going high. But the most important training will be developing a good cardio vascular fitness and strong legs. Walks up steep grades and cycling hills are good preparation activities.

When on the mountain avoid pressing to the point you are so gassed that you must rest. The altitude will steal your endurance and pushing too hard up high turns into what I call "rest addiction," a vicious cycle of hiking a minute of two until fatigue forces you to rest again, then repeating the cycle. This is partially due to the inability to set a sustainable pace. You end up taking a lot longer and enduring more suffering than if you just plod along, slow and steady. Another tip is anticipating all physical activity will be laborious; by the time your breathing reacts to the demands of activity it will be too late and you will soon find yourself out of breath. Therefore when you get up or otherwise exert yourself, immediately start breathing as if your were already exercising. And as already mentioned, do everything with a little more deliberation, as speed is not possible up high unless you do this all the time.

Forget a well balanced diet that includes vegetables and protein. You want as many calories in you for those two days as you can get. Much of this will be from simple sugars and perhaps carbohydrates from pasta like things. You will be expending upwards to 600Kcal an hour (400 average) while going up hill with a backpack. You can do the numbers.

Leave the kitchen sink at home take enough to keep you warm and calorie loaded.

You will spend many hours in unrelenting uphill walking. Aerobic fitness will be your main goal. As WhoMeWorry has suggested, pick a constant cadence and don't cause yourself to be panting or needing to stop often.

Step/Breath method is an excellent way to get in shape but also to handle a long (11mile uphill) walk. The goal is to maintain your heart rate at a consistent steady rate (within reason). Somewhere around 80% of your maximum is sustainable for most who have spent time getting ready. One way to get close to this rate is to take on a LONG set of stairs or a long steep grade after a 15 minute warm up period, start a test run.

Inhale and put the right (or left) foot forward. Exhale when that same foot strikes again. In other words, you perform an respiration cycle for each right to right foot stride. Establish a rate of stepping and breathing that you can maintain for at least 15 minutes but that is somewhat uncomfortable to keep going. It definitely is not a stroll. That would be around 80% of max. This 'slower' rate allows you to exercise at a higher rate longer. You will probably find you are hungry. You need enough nourishment to keep up an exercise program. Eat well balanced equal sized calorie meals often, maybe 6-8 times a day and drink loads of water.

While hiking if you find you need more air take shorter steps, if you are not working at it hard enough, stretch out your stride. The trick is to establish a constant breathing rate that does not cause you to stop often. The longer you can maintain this level of effort the more 'fit' you are.

If you have to stop often you are maxing your body out. Do this too often and you will suffer the next day from the bad management of energy today.

Working out at a gym under some infrequent supervision from a trainer is worth the money spent - especially if you can get somebody who loves/cares for you and is willing to get a membership and a few hours from the staff. Tell them you want 75% of the time on the muscles below your belly button and the rest above it. Pumping iron (or the equivalent on machines) brings surprising advantages to hiking and well worth the extra time/effort. Plan on every other day at the gym working different sets of muscles every other time. This allows the muscles time to recover.

Leave extraordinarily early from the parking lot. You will hopefully get an earlier start than most of the army of hikers who will be on the trail with you. It also gets you a better camping site as high up as you can get the first day. Rest eat and drink lots the rest of the day

Start getting used to drinking more water than you think is ever needed to keep your body going. By the time you are thirsty at altitude, you are already dehydrated.

If you make it a two day trip leave even earlier the next day... perhaps midnightish. You want to beat most of the crowd to the handrails/cables/switchbacks AND be off the top before noon, to beat any storms and certainly before the lightning starts up there.

Be sure you take rain/wind jacket and 200 Polartek equivalent fleece to the top with you. Slather on the UV lotion and lip protection so you don't end up a crispy critter and wear a brimmed hat that will not be blown off and many miles away.

It is a trip of a lifetime, beautiful and exceedingly rewarding.

Aside: If you are susceptible to altitude problems, you might consider a day hike of Whitney getting back to lower altitude before the body catches on it is up too high. At any rate, if you get ill because of altitude, don't try to tough it out just to get to the top. The risk is too high for the bragging rights of the summit. Next time plan on taking longer to acclimatize and get some pharmacy help.

On a steep grade, I like my 'rest step' to be an extended trailing leg 'locked' knee stop/rest before my leading foot pulls me up a few more inches closer to that pass that seems to never get closer. But the rule is: what ever works for you, does.

I did neglect to mention that you will end up breathing in on one foot and exhaling on the other when you start getting close to your 'summit' heart rate. If you are inhaling and exhaling on the same foot plant (gasping and only able to answer yes/no questions), you are no longer breathing aerobically and need to slacken your pace, make your steps closer together, be more fit next time - or all of the above. This doesn't really apply at very high altitude - everybody is slowly suffocating.

Once you have an oxygen deficit, it is difficult to catch up. Before you start an uphill stretch that is coming up start the step breathing sequence 20 seconds (or so) before you start uphill. It takes that long for oxygen molecules to pass your teeth and get to leg muscles. That is why you can run quite a distance before you start panting. It takes awhile for the muscles to become aware they need more oxygen, then it takes awhile for the correct message to be sent to the brain and get management's attention to tell the lungs and heart to start pumping for more air, then it takes more time for it to be assimilated and pumped through the vascular system to where it is needed at the end of itzybitzy plumbing. Best to manage the inventory of air and energy and have it ready before it is needed.

Also, you can pick up a fraction of an inch with each step if you can keep your toes pointed forward rather than splayed to the sides. On a flat track, while walking briskly, you will make about 2000 foot steps (right/left). On an uphill trail you will perhaps be making more than twice as many strides - it adds up and gives you something else to think about.

Trek poles (need both or you will be mostly carrying the one you do have) are valuable if you have trained your upper body strength to use them correctly. The strap takes the weight of the thrust not your hands. The weight is transferred directly to your skeleton through your wrist bones not your hand tissues. All your fingers do is control the 'flicking' of the poles forward and aim the plant of the tip. If you are able (some gym time needed here) to take 20 pounds on each plant of the trek, for each mile, you will have transferred 40,000 pounds from your legs/feet to your shoulders/arms. The part of your body above your belly button no longer gets a free ride.

Simply taking the weight of your arms off your legs onto the treks is a considerable energy redistribution in 11 miles.

After the first half hour or so of the day's hike (or on the trail after a long rest such as lunch or a nap), stop, take off your pack and do some very light stretching of lower and upper legs, glutes, back, shoulders, tummy and back and a few really deep chest expanding breaths each followed by the biggest yawn you can come up with. The stretching probably doesn't do you that much good, but it gives the body and the brain the time it needs to catch up. You are going to really abuse you body over the next 22 miles. Might as well let it be up to the task too.

After a hard day of walking (especially when you get back to the car), after an hour's rest or inactivity, stand up and walk around for 15-30 minutes or so. It will tend to keep you from being a cripple in the morning. When you get home after being a zombie in the car, walk around the block a couple of times in comfortable footwear before you go to bed.

One last suggestion. Start and stay slowly. Don't be tempted to show off how fast you can go or try to keep up with the ones that will be passing you on the first couple of miles. Show off how you can manage your energy over time and get to the top.

Don't forget to include plenty of "Kodak Moments". Er, since Kodak is reorganizing, maybe I should say "Imaging Moments". The scenery is so spectacular that you will want to preserve many images of that trip. At the very least, take a small, light, point&shoot camera that you can hang around your neck where you can grab it instantly. Some of my most memorable images were taken on my first hike up Whitney at age 15, my first Big Mountain - I still feel the thrill many decades later when I look at them, even though they are black and white and even though I have climbed many more technical and challenging routes and in many other countries.

I was advised to snack often, drink lots of water and pace yourself. I kept making myself slow down and it does get hard the last two miles. Getting an early start helps you get back down before dark (Portal to Portal). I headed up at 5 in the morning. I spent a couple days in the area before heading up, checking out Horseshoe Meadow and Chickenfoot Springs for some activity and to get acclimated a little. This helped point out a potential blister, which I took care of at the drug store in town and thus made my trip doable. Reserve a campsite at the Portal area.